Alessandro Dai Pré, Luca Marchetto, Maurizio Grigiante

Abstract: Heat exchangers play a crucial role in various industries, with increasing demand for innovative and efficient designs. Pillow Plate Heat Exchangers (PPHEs) offer promising advantages, yet their potential remains underexplored, particularly in small-scale applications. This study addresses the gap in understanding the thermo-hydraulic behaviour of compact PPHEs by investigating a novel Small-Scale Pillow Plate Heat Exchanger (SSPPHE) designed using the effectiveness-NTU (ε-NTU) method. We developed and experimentally validated a design approach for SSPPHEs with the smallest achievable geometric parameters. Our methodology combines theoretical modelling with rigorous experimental testing, utilizing water as the working fluid in both channels. Key findings reveal that the ε-NTU model predictions align well with experimental data, with thermal power and efficiency deviations within ±15%. However, we observed an underestimation of 15-30% in the Darcy friction factor, highlighting the significance of border effects in compact designs. This research not only validates the applicability of existing correlations to SSPPHEs but also provides critical insights into their performance characteristics. Our findings pave the way for more efficient and compact heat exchanger designs, with potential applications across various industries, from microelectronics cooling to energy systems.

Keywords: Pillow plate heat exchanger (PPHE), Effectiveness-NTU method, Experimental validation.

Date Published: February 4, 2025
DOI: 10.11159/jffhmt.2025.004

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